Semiconductor microchips and integrated circuits (ICs) containing analog, digital and RF elements require some level of protection from cracking and crack propagation during the dicing process, as well as protection from moisture penetration. If the chip were to experience either one of these phenomena (i.e., cracking or moisture penetration), the chip's performance will degrade and the chip will experience reliability issues that could potentially result in catastrophic failure of the chip.
To combat this, “crackstop” wall structures have been fabricated and employed to block a propagating crack from entering the inner core of the chip. Such protective wall barriers are found around the periphery of the chip and surround the inner core of the chip, thus forming a continuous ring framing the IC chip.
Typically these walls are made into continuous ring structures that are completely connected walls with absolutely no holes, voids, breaks, gaps or perforations that a crack or moisture could utilize to bypass the blockade or barrier and enter the IC chip core. Such a continuous ring structure prevents moisture degradation and crack propagation. However, due to the unbroken/continuous nature of these walls, essentially one creates an endless ring surrounding and encircling the IC chip core. Employing such a solid metal continuous wall may inadvertently generate and propagate an unwanted noise/signal or crosstalk signal that can interfere with other elements of the chip and the chip's overall activities, operations and performance.
Noise/signal crosstalk generation occurs when a noise source (e.g., digital signal input/output pad, clock input pad, power amplifier, etc.) located within the chip generates noise that is accidently propagated along the continuous solid metal seal wall and undesirably interacts with other elements located within the chip. To alleviate this noise generation and propagation phenomena along the solid continuous metal seal wall, the wall is typically broken up into segments. A significant disadvantage with having an IC seal ring with intermittent interruptions is that such a design inadvertently creates paths that allow for moisture to diffuse and penetrate into the IC's core region, resulting in degradation and eventual failure of the device. These paths also allow cracks to reach the IC's core region, resulting in reliability and failure issues.